Effects of the Degree of Beak Trimming on the Performance of White Leghorns

Abstract

Three experiments utilizing pullets from hatcheries using different beak trimming techniques were conducted to determine the effects of degree of beak trimming on the performance and welfare of White Leghorns. The methods used to modify beak length were: Exp. 1- infrared (IF) varying guide-plate hole sizes (H, Strain 1); Exp. 2 – IF varying IF intensity (I, Strain 2); and Exp. 3 – hot-blade (HB) varying guide-plate hole sizes (H, Strain 3). Beak treatments included control (C), and an attempt to remove 20, 40 and 60% of the beak of day-old chicks. Pullets were housed on litter floor pens for the brooding and rearing period (0-17 wks) and commercial cages for the laying period (17- 59 wks). Performance records were initiated at 19 wks and continued until 59 wks of age. Altering beak length was successful for Exp. 3 only, achieving 14, 31 and 39% reduction in length for the respective treatments. IF methods achieved 30 to 36% reduction regardless of the severity goal. A reduction in growth during part of the brooding and rearing period which continued throughout the duration of the trial for the 60% severity of Exp. 3. Feed intake was reduced in treated birds of Exp. 1 and 3, but not Exp. 2. Hen- day egg production, egg weight and specific gravity were unaffected. However, hen- housed egg production was reduced for the controls of all experiments due to an increase in mortalities. Behaviour observations via scan sampling indicated pain 1-d post- treatment in Exp. 3 by a decrease in running and litter pecking and a non-significant increase in resting. Minor effects of IF treatment were seen 1-d post-treatment, suggesting reduced or a lack of pain. An apparent but inconsistent effect of both HB and IF treatment was showed increase in object pecking throughout the trial. A general decrease in aggressive behaviour in treated birds of all experiments was noted. Feather condition improved for all treated birds. In conclusion, beak trimming regardless of technique or severity caused minor effects on hen performance while improving welfare conditions relating to decreased aggression and mortalities and an improvement in feather condition.